One way of labeling containers, such as beverage bottles, for example, is by drawing tubular film sleeves over the container's outside surface. As an alternative to the heat-shrinking of film sleeves, which is described, for example, in WO 2007/060705 A1, elastically deformable film sleeves are being viewed with increasing interest due to the lower consumption of material and energy.
For example, WO 2000/066437 describes a method and a device for applying elastic film sleeves to containers. A film tube in a dispenser unit is hereby pulled over a central pin and the film sleeve is separated from the label tube at the required length and pulled, from the top, over two half-shell-shaped forceps halves. With these, the film sleeve can be stretched for the subsequent labeling, whereby a multiplicity of such units revolves on a labeling carousel. The forceps halves are thereby moved apart from one another with the help of a cam controller and the film sleeve is elastically stretched out so far that it can be pulled over a bottle provided below. The stretching devices are lowered for this purpose by cam-controlled lifting devices.
This device has the disadvantage, however, that the half-shell-shaped spreader forceps allow only a relatively minor stretching of the film sleeves and that the movements of the stretching devices and the bottle that is to be labeled are essentially accomplished by mechanical control cams that can only be adapted to different bottles and/or labels with a great effort. In this connection, WO 2000/66437 mentions only a motor-driven lifting support during the lifting/lowering of the stretching device in order to reduce its traversing times and minimize the dimensions of the device. In spite of this measure, however, the described method is suitable only for labeling essentially cylindrical outside surfaces and slightly varying bottle diameters.
For the labeling of curved outside surfaces with highly elastic film sleeves, WO 2008/076718 describes a device in which the half-shell-shaped forceps elements are replaced by a plurality of spreading fingers grouped circumferentially around a central opening and essentially running parallel to one another. The spreading fingers can be slid radially with respect to the central opening and can be moved apart from one another so far that a film sleeve drawn over the spreading fingers is stretched by the spreading fingers and a bottle that is to be labelled can be slid upwards through the central opening.
WO 2008/076718 furthermore describes that the film sleeve is first fixed in place by applying negative pressure on the suction openings provided in the spreading fingers, and can be repelled from the spreading fingers by subsequently applying a positive pressure so that during the further advancing of the bottle to be labeled, a transfer of the film sleeve from the spreading fingers to the bottle results. The radial movement of the spreading fingers is hereby triggered by a rotatable control disc with curved guide grooves for control cams provided on the spreading fingers. A pneumatically or electromechanically controlled actuator arm is suggested as the drive for the control disc. WO 2008/076718 leaves open, however, how such a comparatively complicated drive for the control disc could look. Only cam-controlled control discs are known from commercially available variants of the device described in WO 2008/076718.
Consequently this device also has the disadvantage that an adjustment of the stretching unit to different film sleeves and/or bottles is possible only with a great apparatus-based effort. In other words, numerous mechanical components would have to be interchanged for this purpose. This necessitates not only a high financial expenditure for the provision of the different system components, but also a comparatively long production standstill during the changeover of the labeling machine. Furthermore, the cam controller of the stretching unit known in the state of the art has the disadvantage that the time sequence of the label dispensing and the label stretching is tied to the circulation speed of the stretching units. This means that when there is a change in the machine performance of the labeling device, there is a change in the time sequence of the receiving, stretching and peeling of the film sleeve, as a result of which correct labeling is no longer guaranteed. Devices from the state of the art work in a performance-dependent manner, i.e., they are consequently dependent on the machine speed.
There is consequently a need for a device for applying elastic film sleeves to containers that is improved in this respect, as well as for a correspondingly improved method.